Raised if patch could not be applied due to conflict situation such as:
- attempt to add object key then it already exists;
- attempt to operate with nonexistence object key;
- attempt to insert value to array at position beyond of it size;
- etc.

The “object_pairs_hook” parameter is used to handle duplicate keys when
loading a JSON object. This parameter does not exist in Python 2.6. This
methods returns an unmodified json.load for Python 2.6 and a partial
function with object_pairs_hook set to multidict for Python versions that
support the parameter.